The present invention relates, generally, to lift attachments, and, more particularly, to load bearing attachments mounted to multipurpose loader buckets for earth moving equipment.
Heavy earth moving equipment typically includes multi-purpose loader buckets or backhoes which are well adept for moving and hauling sand, gravel, landfill or the like. Due to their versatility, speed and loading capacity, these front-end loaders are especially suitable for construction, excavation and agricultural applications. Typically, a tractor or the like is fitted with a pair of hydraulically driven lift arms which raise, lower and pivot the multi-purpose bucket for earth moving use.
While these front-end loaders are quite versatile to perform multiple earth moving functions, these buckets are inadequate for moving bulky or elongated items which are unable to fit therein such as large rocks, beams and pipes. Often, a separate forklift vehicle must be employed to perform these hauling tasks. This of course substantially adds to construction costs, as well as consumes space.
As a result, various implements have been developed which adapt these buckets for forklift use. Such adaptations not only increase the versatility of the front-end loaders, but they eliminate the cost and burden associated with the use of separate forklift vehicles. These implements generally include two or more forklift members fixedly spaced-apart from one another, and removably mounted to a lower support member of the front-end loader bucket. Usually, these forklift members extend under the loader bucket support member for structural mounting thereto, while a clamping assembly is employed to releasably clamp the forklift members to a leading edge portion of the support member. A rear portion of each forklift member is then mounted to an upper rear portion of the loader bucket for stability. Typical of these patented designs are disclosed in U.S. Pat. Nos.: 4,411,585; 4,242,035; 4,125,952 and 3,706,388.
While these forklift implements are adequate for hauling and carrying relatively low to middle weight items (i.e., under 10,000 lbs), the lifting of heavy weight objects may cause severe damage to the implement and/or the loader bucket. Due to the extreme cantilever forces concentrated at contact points along the leading edge of the lip portion, the clamping assembly of the implement and/or the lip portion of the bucket leading edge may be caused to irreparably bend or deform during heavy weight use. Consequently, repair or replacement costs can be substantial.
Other forklift implements have been developed which are primarily supported atop the support member of the loader bucket. However, these designs similarly fail to distribute the cantilever forces across the loader bucket. During heavy load use, the extreme cantilever forces are also concentrated at contact points along the leading edge of the lip portion. Typical of these patented structures are disclosed in U.S. Pat. Nos.: 4,329,103 and 3,667,633.
Thus, a forklift implement for use with a front-end loader is desirable which can accommodate relatively heavy weights without damaging the loader bucket and/or the implement.
To achieve the foregoing, the present invention relates to a load bearing lift attachment apparatus for a multipurpose loader bucket. A first jaw of the loader bucket is movably mounted to a second jaw thereof between an opened condition and a closed condition. The first jaw includes a support member transversely extending from one side to an opposite side of the loader bucket. A front portion of the loader bucket terminates at a transversely extending leading edge, while an opposite rear portion thereof terminates at a rear edge. The second jaw includes an engaging wall transversely extending from the loader bucket one side to the opposite side thereof. The engaging wall further terminates at an engaging edge, and is formed to engage the rear portion of the jaw support member in the closed condition. The lift attachment apparatus of the present invention includes a lift member formed and dimensioned to engage an object to be lifted; and a support device removably coupling the lift member to the loader bucket. The support device includes a load bearing member formed to extend transversely across an upper surface of the first jaw support member for support thereatop. An elongated rear coupling member is sized and structured to simultaneously engage the rear portion of the support member of the first jaw, and the top surface and the bottom surface of the engaging wall of the second jaw, in the closed condition, to distribute the cantilever forces, caused by the weight of the object acting on the loader bucket, across a substantial transverse portion of the support member of the first jaw and the engaging wall of the second jaw.
In one configuration, the elongated rear coupling member includes an alignment lip in abutting contact with the bottom surface of the engaging wall of the second jaw for supportive alignment thereof, when in the closed condition. The elongated rear coupling member further includes a contacting portion having a forward surface and an opposed rearward surface. Each surface extends transversely across a substantial portion of the rear edge of the first jaw support member. The forward surface is in abutting contact with the rear edge, and the rearward surface is in abutting contact with the engaging edge of the engaging wall, for supportive alignment therebetween, when the loader bucket is in the closed condition.
The rear coupling member further includes a lower lip portion extending rearwardly from the rearward surface of the contacting portion, to a position under the bottom surface of the engaging wall. The alignment lip extends upwardly from the lower lip portion, toward the bottom surface of the engaging wall, for the abutting contact therewith.
In another embodiment, the lift member includes an elongated forklift prong portion extending forwardly of the load bearing member. The lift member includes a track assembly slideably mounting the lift member to the load bearing member to facilitate sliding displacement of the lift member laterally therealong. Preferably, the track assembly includes a support rod extending longitudinally across and substantially parallel to the rear coupling member. The lift member includes a receiving passage formed and dimensioned for sliding receipt of the rod longitudinally therethrough for sliding lateral displacement of the lift member laterally along the load bearing member portion.